A nozzle beam to produce streams of liquid is known for example from EP-A0 725 175. Water streams emerge at high pressures of up to 600 bar from the nozzle slot located in the lower part of the beam and strike the web of goods passing by immediately beneath, held by a substrate. The water streams are exposed beneath the substrate to suction intended to carry away the liquid. Practice has shown however that not all of the liquid sprayed can be drawn off immediately, but a portion is reflected off the goods, at the substrate, and sprayed back against the underside of the nozzle beam. From there this liquid then drips onto the web of goods, which is to be avoided.
It is known from practice to arrange a liquid-catching device at least on one long side of the nozzle beam parallel to its length and in the immediate vicinity of the outer edge of the lower part, said device being intended to catch the liquid running off the underside of the nozzle beam.
The goal of the invention is to improve a fluid catching gutter of this kind in such fashion that it immediately receives completely the fluid that reaches the underside of the nozzle beam, possibly including a water fog that is produced when spraying.
On the basis of the device of the type recited at the outset, the solution that has been found consists in the fluid-catching device being designed as a suction tube with a lengthwise suction slot located as a suction tube with a lengthwise slot providing suction along the underside of the nozzle beam. The fluid is therefore not only to be caught but immediately drawn away along the entire beam. It is advantageous to produce the vacuum in the catching device by means of the pump that also provides the vacuum in the suction slot at the substrate.
In order for the vacuum that can be produced in the tube enclosed on all sides or the like to act uniformly over the length of the nozzle beam, the depth of the suction slot should be small, for example 1-5 mm. It is advantageous for this suction slot to be located at the end of a funnel and for the funnel to extend by its underside up to and even beneath the underside of the nozzle beam. There is little space available were since the goods to be treated must be guided very close to the outlet of the water stream from the nozzle sheet. This is particularly true when the substrate is an endless belt; slightly more space is provided when the substrate is a screen roller which, because of its curvature, leaves more room for a closer arrangement of the suction funnel. The invention proposes a solution for this arrangement and a special design which will be described in greater detail in conjunction with the example shown in the drawing.